def mod(a, b):
    """
    Returns the  modulus after division.

    Args:
        a,b (float or list of lists of float) 

    Returns:
        float or list of lists of float:the modulus after division.
    """
    if isinstance(a, (int, float)) and isinstance(b, (int, float)):
        return a % b
    elif isinstance(a, (list, tuple)) and isinstance(b, (int, float)):
        return [x % b for x in a]
    elif isinstance(a, list) and isinstance(b, list) and len(a) == len(b) and isinstance(a[0], list) and isinstance(b[0], list) and len(a[0]) == len(b[0]):
        # Create an empty matrix to store the results
        result = [[0 for j in range(len(a[0]))] for i in range(len(a))]
        # Loop through each element and find the modulus after division
        for i in range(len(a)):
            for j in range(len(a[0])):
                result[i][j] = a[i][j] % b[i][j]
        return result
    else:
        # Raise TypeError for unsupported input types
        raise TypeError("Input type not supported.")


# Test case 1
assert mod(7, 3) == 1

# Test case 2
assert mod(-7, 3) == 2

# Test case 3
assert mod(7, -3) == -2

# Test case 4
assert mod(4.5, 1.5) == 0.0

# Test case 5
a = [1, 2, 3, 4]
b = 3
assert mod(a, b) == [1, 2, 0, 1]

# Test case 6
a = [[1, 2], [3, 4]]
b = [[2, 2], [2, 2]]
assert mod(a, b) == [[1, 0], [1, 0]]
